Having taken as a bow the great weapon of the Secret Teaching,
One should fix in it the arrow sharpened by constant Meditation.
Drawing it with a mind filled with That (Brahman)
Penetrate, O bright youth, that Immutable Mark.

The pranava (AUM) is the bow; the arrow is the self;
Brahman is said to be the mark.
With heedfulness It is to be penetrated;
Become one with It as the arrow in the mark.

Know that Self alone, the One without a Second,
On which are strung Heaven and Earth,
Inner Space, Mind, Vital Energy, All the organs.
Leave off other words, for this is the Bridge to Immortality.

Mundaka Upanishad